Method for singulating semiconductor substrate by etching front and back surfaces of semiconductor substrate

A method for singulating a semiconductor substrate into individual semiconductor devices, comprising:

• providing a semiconductor substrate having a front surface and a back surface, wherein the semiconductor substrate comprises device regions that are separated from each other by respective predetermined saw streets, wherein the semiconductor substrate comprises an active layer that is exposed from the front surface and a bulk layer further below the active layer;
• forming an interconnect layer on the front surface of the semiconductor substrate;
• etching the front surface of the semiconductor substrate at the predetermined saw streets to form respective frontside openings each having a first depth, wherein the first depth is smaller than a thickness of the semiconductor substrate, wherein etching the front surface of the semiconductor substrate comprises:
• patterning the active layer of the semiconductor substrate at the predetermined saw streets to form respective active windows that expose the bulk layer;
• and
• etching the front surface of the semiconductor substrate at the active windows using deep reactive ion etching process;
• attaching a semiconductor element onto the front surface of the semiconductor substrate in each device region;
• and
• etching the back surface of the semiconductor substrate at the respective predetermined saw streets to form respective backside openings each having a second depth, wherein each frontside opening is at least partially aligned with the backside opening at the same saw street to singulate the device regions of the semiconductor substrate into individual semiconductor devices.